The appearance of a low fuel warning light is not usually a cause for celebration, but I must admit I was feeling quite cheery when it happened in the XC60. The trip computer told me that the 612 miles had passed since the car was last filled up, and that it had taken an average of 45.6 of those miles for me to burn my way through each gallon of diesel.Economy statistics displayed by trip computers are not always very accurate, but even assuming a reasonable margin of error I thought that 45.6mpg was a mightily impressive figure for a car the size and weight of an XC60 - especially since a small and apparently economical diesel supermini I drove at about the same time claimed no better than 47mpg.Not every XC60 would be able to do this, of course. Economy of this sort is achievable within the range only by the DRIVe, whose major selling point is its ability to sip fuel delicately and emit low levels of CO2. It can do this thanks to a range of features - not the disc-like aerodynamic wheels which make other DRIVe models look somewhat less than elegant, but including the most economical engine in the range (a 173bhp 2.4-litre turbo diesel which replaced the less powerful version available when the car was launched late last year), the only low-rolling resistance tyres I've ever encountered which you can actually feel working, higher gearing and, uniquely among XC60s, front- rather than four-wheel drive.The lack of a 4x4 system no doubt compromises the DRIVe's ability off-road, but this probably isn't a concern for most XC60 owners anyway. Likewise, dividing 173bhp between two wheels rather than among all four might cause problems if you're pushing the car hard on tarmac, but nothing about the car encourages you to do that. Volvo's claim that the XC60 "drives like a top quality compact sporting car" is just plain silly, and I doubt that anyone in the company really believes it.The positive side of this is that if there is no incentive to go quickly you're more likely to match the official combined fuel economy figure, as I nearly did. All the same, I wouldn't complain if the handling were made slightly sharper than it is now, and while I'm in a complaining sort of mood I might mention that long journeys are less comfortable than they might be because the seats aren't very supportive (or at least they don't suit me) and there isn't a proper foot rest, while reversing is needlessly difficult because of the very restricted rear view.But if I needed an SUV of this size I would probably be drawn towards the XC60 DRIVe because of its impressive economy, and also because of the City Safety feature. If I had to name one reason to buy an XC60, this would be it. City Safety is designed to help prevent low-speed impacts, and you can read more about it in our launch review. Fortunately I didn't have an opportunity to reacquaint myself with the system during this test, but it was nice to know it was there.City Safety is one of a multitude of safety aids standard on all XC60s, the others being ABS, EBD, brake assist, dynamic stability and traction control, roll stability control, rollover protection, side impact protection and whiplash protection. SE models, such as the one tested here, also come with an electrically-adjustable driver's seat with three memory functions, folding door mirrors with ground lights, Eriksberg upholstery, chrome window trim and an auto-dimming mirror with a digital compass display, none of which are standard on the entry-level S model. (Some SEs have hill descent control too, but not the ones fitted with the 2.4D engine.)DRIVe models are also available in SE Lux specification, which includes leather upholstery, wood trim, heated front seats, 18" alloy wheels, cornering lights, a much-needed rear parking sensor and more chrome, while both SE and SE Lux versions can be specified with a Premium Pack which, for £2000, adds satellite navigation and more leather. Engine 2400 cc, 5 cylinders Power 175 bhp @4000 rpm Torque 310 ib/ft @1500 rpm Transmission 6 speed manual Fuel/CO2 47.1 mpg / 159 g/km Acceleration 0-62mph: 9.8sec Top speed 127 mph Price From £27256.00 approx Release date 01/06/2009